Technical Field
The present invention relates to a technique for preventing rotation of an inner cylinder connected with an overhead wire in an overhead wire tension balancer in which tension is applied to the overhead wire for a train or a vehicle (a trolley bus, etc.).
Background Art
Patent Document 1 discloses an overhead wire tension balancer having a structure in which a slidable long plate is inserted into a guiding hole on a rotation preventing plate in a condition in which it cannot be rotated. Patent Document 2 discloses a locking structure in which a rigid portion (a stopper) for hanging on a circumference of a hole on an end surface of an inner cylinder is formed at a tip of a guiding plate (a pipe), so that a stroke does not exceed a fixed range.
Patent Document 1 is Japanese Unexamined Patent Application Publication No. Hei11-48834. Patent Document 2 is Japanese Unexamined Patent Application Publication No. Hei09-207629.
In the technique described in Patent Document 1, there is a problem in that the long plate may disengage from the rotation preventing plate, in a case in which the overhead wire tension balancer is pulled by the overhead wire, so as to increase the stroke. When the long plate disengages from the rotation preventing plate, a function that prevents rotation of the inner cylinder connected with the overhead wire is decreased. Furthermore, in the case in which the overhead wire tension balancer is decreased in size, the long plate does not return to an original condition.
Here, according to the structure having the stopper described in Patent Document 2, the long plate can be prevented from disengaging from the rotation preventing plate. However, the number of production steps and the production cost are increased by assembling the stopper.
In view of these circumstances, an object of the present invention is to provide an overhead wire tension balancer for applying tension to an overhead wire in which rotation of an inner cylinder connected with an overhead wire can be prevented, and a rotation preventing function will not deteriorate, even if stroke is increased, and moreover, increase in the number of production steps and production cost can be avoided.